488 U.S. 445 (1989) (U.S. Supreme Court)
Florida v. Riley is a cornerstone Fourth Amendment case addressing whether aerial surveillance of a home's curtilage from a helicopter constitutes a search requiring a warrant.
Does police observation of the curtilage of a home from a helicopter at 400 feet, using only the naked eye and without a warrant, constitute a search under the Fourth Amendment?
Under Katz, a search occurs if the government violates a subjective expectation of privacy that society recognizes as reasonable. Applying that test to aerial surveillance of curtilage, observation from aircraft in public navigable airspace using the naked eye generally is not a search if (1) the flight occurs at an altitude and in a manner used by the public with sufficient regularity such that the area is exposed to public view, and (2) the surveillance is not unduly intrusive (e.g., causing significant noise, wind, dust, threat of injury, or physical interference). Compliance with FAA regulations is relevant but not dispositive of whether the expectation of privacy is reasonable. (Justice O'Connor's concurring opinion provides the controlling, narrowest grounds under Marks v. United States.)
No. Observing Riley's greenhouse from a helicopter at 400 feet did not constitute a Fourth Amendment search under the circumstances; therefore, the warrant based on those observations was valid and the evidence need not be suppressed.
Florida v. Riley refines the Fourth Amendment analysis for aerial surveillance after Ciraolo and Dow Chemical. Because the decision lacks a single majority opinion, Justice O'Connor's concurrence is the controlling rule: courts should ask whether the public commonly occupies the vantage point and whether the surveillance was unduly intrusive, with FAA regulations as a non-dispositive data point. The case underscores that even curtilage may be exposed to lawful aerial observation, but it preserves meaningful limits tied to common public use and intrusiveness. For students and practitioners, Riley is essential for understanding the Katz framework in nontraditional contexts, how to apply Marks to fractured opinions, and how evolving technologies (e.g., helicopters, drones, sensors) may recalibrate reasonable expectations of privacy.